open AFILE, "<C:\\Documents and Settings\\R19338\\Desktop\\2.txt";
my %lines;
while(<AFILE>) {
    $lines{$_} = $_;
}


open EFILE, "<C:\\Documents and Settings\\R19338\\Desktop\\1.txt";
open WFILE, ">C:\\Documents and Settings\\R19338\\Desktop\\3.txt";
while(<EFILE>) {
    if (!exists($lines{$_})) {
        print (WFILE $_);
    }
}